Abstract
Neutron and x-ray scattering measurements were performed on (Na1/2Bi1/2)TiO3-xat%BaTiO3 (NBT-xBT) single crystals (x=4, 5, 6.5, and 7.5) across the morphotropic phase boundary (MPB), as a function of both composition and temperature, and probing both structural and dynamical aspects. In addition to the known diffuse scattering pattern near the Γ points, our measurements revealed new, faint superlattice peaks, as well as an extensive diffuse scattering network, revealing a short-range ordering of polar nanoregions (PNR) with a static stacking morphology. In samples with compositions closest to the MPB, our inelastic neutron scattering investigations of the phonon dynamics showed two unusual features in the acoustic phonon branches, between the superlattice points, and between the superlattice points and Γ points, respectively. These critical elements are not present in the other compositions away from the MPB, which suggests that these features may be related to the tilt modes coupling behavior near the MPB.
| Original language | English |
|---|---|
| Article number | 174108 |
| Journal | Physical Review B |
| Volume | 96 |
| Issue number | 17 |
| DOIs | |
| State | Published - Nov 10 2017 |
Funding
Authors C.L. and D.V. would like to thank the ONRL-GO program for support of this work through the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. DOE, and J.F.L. would like to thank the Office of Naval Research for the support of this work (N00014-13-1-0049). O.D. and D.B. acknowledge funding from the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division, under the Early Career Award No. DE-SC0016166. Authors X.L. and H.L. acknowledge the National Natural Science Foundation of China under Grants No. 51332009 and No. 61634007. The use of Oak Ridge National Laboratory's Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357.